Took a profile of the "Smart Cover" page on Apple's site using Pingdom. It's requesting 241 objects for a total page weight of 3472.6 KB! An absolute mammoth.
How does this possibly translate into a 4-second download time? I'm not even on a great connection and it still loads in seconds using my clogged-up DSL. That interactive graphic towards the middle loads over 90 images per selected cover, at around 40k each. Still, it's done at blazing speeds.
How do they do it?